Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PRDP, Final > 4. Direct and Indirect Retainers > Flashcards

4. Direct and Indirect Retainers Flashcards

1
Q

Direct Retainer

 The component of a PRDP used to retain and prevent ____ consisting of a clasp assembly or attachment

A

dislodgement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q 
Intracoronal - attachment placed into a crown NOT on the outside; often
incorporated into
provisional bridges & are
nice bc they don’t show
clasps.

2 Systems- indicative of how tight attachment
connects to crown:

\_\_\_\_ - fits v tightly /
not loose; designed NOT
to release stress.
KC3 - bc it’s entirely
supported by abutment
teeth

____ - these
attachments “give” more Sometimes made w a ring + nylon (e.g. for
overdentures, we want
these prosths to be
supported/retained by the attachment BUT don’t
want it to torque the
abutment tooth.)

A

precision

semiprecision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Extracoronal - attachment is on outside of the crown (e.g. a ring soldered to the ____ aspect of a crown w an attachment that fits into it)

Retentive class
assembly - most
\_\_\_\_; fits around
the tooth; 2 types
indicating where bulk
of clasp is located:
\_\_\_\_ ⿞
(clasp is above
height of contour
except the
retentive tip,
which flexes over
to engage)
\_\_\_\_ ⿞
(below HOC)
A

distal
common
suprabulge
infrabulge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Clasp Assembly

The part of a PRDP that acts as a ____ for a prosthesis by ____ encompassing or contacting an abutment tooth

A

direct retainer

partially

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Terminology
Suprabulge
 the surface of a tooth that is occlusal of the ____

Infrabulge
 the surface of a tooth that is ____ of the height of contour

A

height of contour

gingival

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Types of Clasp Assemblies
 Suprabulge
 ____ or circumferential
 Approaches ____ from the occlusal (____ height of contour)

 Infrabulge
 ____ or bar
 Approaches undercut from the ____ (____ height of contour)

A

Aker’s
undercut
above

roach
gingival
below

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Clasp
That component of a clasp assembly that engages a portion of the tooth surface and either engages an undercut or remains above height of contour

Composition
 Cast ____
 Wrought wire

 Configuration
 \_\_\_\_ 
 Bar
 Combination
 Circumferential and bar
 Cast clasp arm and wrought wire clasp

Primary function
 ____
 Bracing (____)

Directional approach to
the undercut
 ____
 Infrabulge

A 
metal
circumferential
retention
stabilizing
suprabulge
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Retention
Resistance to ____ dislodging forces
Provided by the retentive clasp arm
 Divided into three parts:
 Proximal 1/3 (shoulder)- must be ____ and located ____ the survey line
 Middle 1/3- must be ____ and ____ the survey line
 Terminal 1/3- must be ____ and engage retentive ____ on tooth ____ the height of contour

A 
vertical
rigid
above
ridgid
traverses
flexible
undercut
below
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Retention
Should be the ____ necessary to resist dislodging forces
Retentive areas on ____ side of the arch should be opposed by retentive areas similarly placed on the ____ side of the arch

A

minimum
one
other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Retention
To be retentive, the terminal end of the retentive clasp must be engaged in ____ area
 Counteract dislodging forces that unseat the PRDP at ____ angles to the occlusal plane during function

A

undercut

right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Retention

 Amount of retention depends on:
1. \_\_\_\_
2. Flexibility of the clasp
arm
3. \_\_\_\_ of the undercut
4. Length
-
– amount of clasp arm extending \_\_\_\_ the height of contour
5. \_\_\_\_
A

material
degree
below
shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Flexibility of a Clasp Arm
Influenced by:
The cross-sectional form
 ____ clasp has greater flexibility than half round clasp with the same diameter

Diameter (cross-sectional size)
 The smaller the diameter of the clasp, the greater the ____

A

round

flexibility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Flexibility of a Clasp Arm
Influenced by:

Length of the clasp
 the longer the clasp, the greater the ____

The taper of the clasp
 The more the taper, the more the ____
 A ____ taper in both thickness and width is necessary
 Clasp terminal should be ____ as thick as origin

A

flexibility
flexibility
uniform
half

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q 
Flexibility of a Clasp Arm
Influenced by:
The material (metal alloy used)
 Flexibility of the retentive clasp arm varies with different alloys used
 \_\_\_\_
 \_\_\_\_
A

cast metal

wrought metal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Wrought Metal Clasps
 Their longitudinal structure allow for greater degree of ____ than the grain structure of cast metal clasp
Are placed in slightly ____ undercuts (____ inch) than are cast clasps

A

flexing
greater
0.02

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q 
Wrought Metal Clasps
Applied by:
 Soldering it to the \_\_\_\_
connector
 Soldering it to the \_\_\_\_
A

minor

meshwork

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

 The B-L depth of retentive undercut and therefore, the position of the terminus of a retentive clasp arm is determined using undercut gauges in a dental surveyor
 0.01” undercut: ____ metal clasp
 0.02” undercut: ____ clasp
 0.03” undercut: ____ used

A

cast chrome
wrought wire
rarely

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Support
Resistance to ____ seating forces (displacement of the clasp assembly in a gingival direction)
Provided by the ____
Prevents ____ to periodontal structures

A

vertical
rests
trauma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q 
Stability (Bracing)
Resistance to \_\_\_\_ components of masticatory force
Provided by
 \_\_\_\_ portions of clasps
 Other rigid components which contact vertical tooth surfaces
 Proximal 
 Facial
 Lingual

Note: Retentive clasp ____ does NOT contribute to ____

A

horizontal
rigid
terminus
stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Reciprocation
Resistance to ____ forces exerted on a tooth by an active clasp during ____ and unseating of the prosthesis
Each retentive clasp arm must be opposed by a ____ arm

A

horizontal
seating and unseating
reciprocal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Reciprocation
Positioned on the ____ side of the tooth from the retentive arm
Should always contact tooth ____ the retentive clasp arm when the clasp is being ____ on the tooth

A

opposite
before
seated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Adequate Encirclement
 Each clasp assembly must engage a minimum of ____° of circumference of abutment tooth to prevent tooth from moving out of contact with clasp assembly
 May engage ____ than 180°

A

180

more

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Adequate Encirclement
Prevent ____ tooth movement from within the confines of a clasp assembly
May incorporate a minimum of ____ widely separated points of contact

A

horizontal

three

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Passivity
A clasp assembly in place should be completely ____ (no active force on tooth)
Only when a ____ force (e.g. force in occlusal direction) is applied to the PRDP is the ____ function activated

A

passive
dislodging
retentive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Requirements of a Clasp Assembly
Retention- ____ necessary
 Support- proper ____
 Stability (bracing)- ____ portions of clasps and minor connectors
 Reciprocation- ____ clasp arm
 Encirclement- ____° or more to prevent tooth
movement
 Passivity- no ____ force by clasp in place

A 
minimum
rests
rigid
reciprocal
180
active
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q 
Commonly used Clasp Assemblies for Tooth- supported PRDP
\_\_\_\_ clasp assembly (Akers)
Embrasure clasp assembly
Cast circumferential and cast bar clasp assembly 
 \_\_\_\_ clasp
 Modified T bar
 \_\_\_\_ bar
 I bar
A

circumferential
T bar
Y

27
Q

Cast Circumferential Clasp Assembly

 Excellent support, bracing and retentive qualities
 Encircles tooth ____ than 180°
 More frequently on teeth ____ to modification spaces
 usable undercut on the abutment tooth is located on the side of the tooth ____ from the edentulous area

A

more
adjacent
away

28
Q

Cast Circumferential Clasp Assembly

Retentive clasp arm
 originates ____ height
of contour
 terminal 1/3 is positioned ____ (engages undercut)

Reciprocating clasp arm
 slightly ____ than the retentive clasp to promote rigidity

A

above
below
thicker

29
Q

Additional Considerations for the Cast Circumferential Clasp
 The ____ of the retentive clasp and the entire ____ of the bracing clasp should be located at the junction of the ____ 1/3 of the tooth occlusogingivally

A

proximal 2/3
length
middle and gingival

30
Q

Proper Position of Retentive Clasp Terminus

 Should not contact the ____
 Should be located at the ____ portion of the gingival 1/3 of the tooth occlusogingivally

A

free gingival margin

gingival

31
Q

Embrasure Clasp
Two ____ clasp assemblies originating from a common ____ connector
Indicated on side of arch where there is no ____ space
Must cross the marginal ridges of ____ teeth

A

circumferential
minor
edentulous
two

32
Q

Embrasure Clasp
Occlusal rests on ____ teeth
Two cast ____ clasps
Two cast ____
clasps
Must provide sufficient space for adequate thickness of metal
 Prepare rest seats and marginal ridges adequately

A

both
retentive
reciprocating

33
Q

Bar Clasps
• Classified by shape of the ____
 T bar, modified T bar,Y bar
• T and Y bar clasp arms are the most ____
• Only ____ of clasp is needed to be placed in undercut area

A

retentive terminal
misused
terminal

34
Q

Bar Clasps
• In many cases the ____ portion of T or Y clasp arm may be removed because they are ____ the survey line and they become ____ T or Y bar clasp.

A

suprabulge
above
modified

35
Q

Bar Clasp
Approach undercut from a ____ direction
More ____ than a circumferential clasp

A

gingival

esthetic

36
Q

Bar Clasp
T bar
 ____ undercut

Modified T bar
 ____ finger omitted (____)

A

DB
nonretentive
esthetics

37
Q

Bar Clasp
Y bar
 ____ are high on M & D but low on ____ of abutment tooth

I bar
 on ____ of canines for esthetics

A

height of contours
center
DB

38
Q

Here’s the T-bar in the ____ 1/3 picking up the undercut at 2 termini. This has been relieved (points in this green highlighted space); this is the approach arm. We don’t want this too high on the tooth.

A

gingival

39
Q

Relationship of Bar Clasp to the Gingiva
• The approach arm must not impinge on the ____ adjacent to the abutment

• The approach arm should cross ____ to the free gingival margin

A

soft tissues

perpendicular

40
Q 
Contraindication to Bar Clasp
• The clasp should not be located over a deep tissue \_\_\_\_
• A great deal of relief
required may
 form a \_\_\_\_
 interfere with patient
comfort
 cause \_\_\_\_ to the mucosa of
the lip or cheek
A

undercut
food trap
injury

41
Q

Additional Design Considerations for the Bar Clasp

• The minor connector that attaches the occlusal rest to the framework should
 be ____
 contribute to the overall ____ and stabilization of the prosthesis

A

rigid

bracing

42
Q

Commonly used Clasp Assemblies for Extension Base PRDP
____ clasp assembly
____ (RPC) clasp assembly
____ and wrought wire circumferential clasp assembly (combination clasp)

A

RPI
RPA
cast circumferential

43
Q

RPI Clasp Assembly/
RPA (RPC) Clasp Assembly
 RPI:
 Rest (____)
 Proximal plate (____)
 Cast ____ bar retentive clasp engaging ____ or mid-buccal ____
 Proximal plate and minor connector provide ____

A 
MO
D
I
0.01" MB
undercut
reciprocation
44
Q

Mechanics of the RPI Clasp Assembly

• Forces are transmitted through the PRDP components to the ____ rest directing mesial torquing and axial forces to the tooth
• Occlusal force causes rotation in the area of ____ rest
• I bar clasp arm and proximal plate ____ from the tooth during function
and move in a ____ direction
• The abutment tooth is braced mesially by an ____ tooth

A 
mesial
mesial
disengage
mesiogingival
adjacent
45
Q

Contraindication for the RPI Clasp Assembly
• No tooth undercut
• Severe tissue undercut
 Clasp arm -no more than ____ mm from the soft tissue
 Excessive relief may form food trap food, interfere with patient comfort or irritate the lip or cheek

• ____ buccal or labial vestibule
 I bar arm should not interfere
with movable tissue
 Superior border of the arm located at least ____mm from the gingival margin

A

2
shallow
3

46
Q

Advantages of the RPI Clasp Assembly
Proximal plate and I bar move ____ from the tooth during function to reduce torque
Mesial minor connector and proximal plate provide ____ and eliminate need for a ____ arm (no need for lingual recontouring)
I bar is more ____
Mesial rest eliminates class ____ lever

A 
away
reciprocation
lingual
esthetic
I
47
Q

RPI Clasp Assembly/
RPA (RPC) Clasp Assembly
 RPA Clasp Assembly:
 Rest (____)
 Proximal plate (____)
 ____ retentive clasp engaging ____ or mid-buccal undercut
 Proximal plate and minor connector provide ____
 Used where RPI clasp is contraindicated
 severe tissue ____
 ____ B vestibular depth

A 
MO
D
akers
0.01" MB
reciprocation
undercut
insufficient
48
Q

Assembly and Mechanics of RPA Clasp

  • Forces are transmitted through RPD components to the ____ rest directing mesial torquing and axial forces to the tooth.
  • Rotation occurs in the area of ____ rest.
  • Circumferential clasp and proximal plate ____ from tooth during function.
  • The abutment tooth is usually braced by a mesial ____ tooth.
A

mesial
mesial
disengage
adjacent

49
Q

Combination Clasp
____ circumferential (reciprocal) clasp arm
A ____ circumferential (retentive) clasp arm
 Indications
 on an abutment tooth adjacent to a distal extension space when the usable undercut is on the ____ surface
 greater ____ of retentive arm is desired
 ____ an advantage

A 
cast
wrought wire
MB
flexibility
adjustability
50
Q

Combination Clasp
 Advantages:
 may be used when a ____ projection clasp is contraindicated because of a soft tissue ____ below the tooth
 can be placed in a ____ undercut area (____”)
 ____ occlusal rest, distal proximal plate

A 
vertical
undercut
deeper
0.02
distal
51
Q

Mechanics of Cast Circumferential and Wrought Wire Clasp (Combination Clasp)

Strategy – Reduce the effective Class ____ lever in distal extension partial by using ____ component in the resistance arm.
• Consists of cast, reciprocal arm and tapered, round wire, retentive clasp arm
• The retentive clasp is either ____ to a cast framework

A

I
flexible
cast or soldered

52
Q

Mechanics of Combination Clasps
• Rotation occurs at area where minor connector breaks ____ with tooth
• Wrought wire retentive clasp tip moves ____ during function and directs a ____ torquing force on tooth
• Magnitude of the torquing force is influenced by the ____ of the wrought wire clasp

A

contact
occlusally
distal
flexibility

53
Q

Advantages of Combination Clasps
• Flexibility- used when maximum flexibility required
 Abutment tooth adjacent to ____ extension base.
 Weak abutment, when a ____ type retainer contraindicated.

  • Adjustability- when precise retentive requirements ____ and later on adjustment needed for retention.
  • Esthetics – less bulkier than cast clasp. Wrought wire small diameter thickness, stronger because ____ in structure. Light reflected in such a way that the appearance of metal less obvious.
  • Minimum tooth surface coverage – less ____ buildup
A 
distal
bar
unpredictable
round
plaque
54
Q 
Disadvantages of Combination Clasps
 Involves extra \_\_\_\_ in fabrication
 Can be \_\_\_\_ by careless handling
 won’t \_\_\_\_ tooth
 It may distort with function and not engage tooth
A

step
distorted
stabilize

55
Q

Ring Clasp
Most often indicated on ____ molars
____ almost the entire tooth from its point of origin
Entire clasp except for the ____ must be placed above the height of contour
An ____ arm is needed to prevent excessive f lexing

A

tilted/tipped
encircles
retentive tip
auxiliary bracing

56
Q

Factors Determining the Selection of Clasp Assembly

A. Distribution of Forces
 ____ of forces to muco-osseous and dento- alveolar segments is required
 ____ clasps minimize lateral torquing forces directed to abutment teeth
 ____ clasps direct lateral torquing forces to the abutment teeth

A

distribution
stress releasing
non-stress directing

57
Q

Factors Determining the Selection of Clasp Assembly
A. Distribution of Forces
 Commonly Used Non-stress Directing Clasp
 ____ (circumferential) clasp
 ____ clasp

 Commonly Used Stress Releasing Clasp Assemblies
 ____ (Rest, Proximal Plate, I-Bar)
 ____ (Rest, Proximal Plate, Akers)
 Cast circumferential and wrought wire circumferential (____) clasp

A

akers
embrasure

RPI
RPA
combination

58
Q

Factors Determining the Selection of Clasp Assembly

B. Location of Undercut
 on ____ tooth will influence choice of retentive clasp arm

C. Minimal tooth and minimal gingival coverage
 Clasps which ____ these tissues are preferred
 Reduce plaque accumulation

D. Esthetics
 Influenced by visibility of clasp 
 Bar clasps
• confined to \_\_\_\_ 1/3 of tooth and contact less tooth surface area
• approach undercut from \_\_\_\_ direction
• are less conspicuous than \_\_\_\_ clasp

E. Clasps on Previous Removable Partial Denture
 May indicate esthetic awareness and demand of patient
 May indicate amount of ____ necessary

A 
abutment
minimize
gingival
gingival
circumferential
retention
59
Q

Indirect Retainer
 “The component of a removable partial denture that assists the direct retainer (s) in preventing ____ of the distal extension denture base by functioning through ____ action on the opposite side of the fulcrum line when the denture base moves ____ from the tissues in pure ____ around the fulcrum line” (GPT, 1999)

A

displacement
lever
away
rotation

60
Q

Indirect Retainer
Should be positioned on the ____ side of the fulcrum line (center of rotation)
At ____ angles to and as far from the fulcrum line as possible

A

opposite

right

61
Q 
Indirect Retainer
Forces causing vertical movement of the denture base away from the supporting ridge:
 pull of \_\_\_\_ foods
 forces created by \_\_\_\_ action 
 \_\_\_\_
A

sticky
muscle
gravity

62
Q 
Indirect Retention
\_\_\_\_ premolar
 an ideal location for an indirect retainer (no opposing maxillary
cusp that occludes into this fossa) 
 Anterior to \_\_\_\_ line (F)
 Resists lifting of denture base
A

mesial fossa of mandibular first

fulcrum

63
Q

Indirect Retention

Without an indirect retainer, the PRDP may ____

A

dislodge

64
Q

Types of Indirect Retainers
____
____ connectors and proximal plates

Others
 ____
 Need rest seats prepared
 Kennedy bar ____ connector

A

rests
minor

lingual plate
major

PRDP, Final (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions